JamesDowning wrote:The larger the radii of any bend, the less stress concentrations will exist.
A mitered edge has an effective 0" radius, and thus there is a big stress concentration right at your weld.
That's why you do as large a fillet weld as you can... I usually either do a weld down in the corner, then a larger (hotter) weld on top of it, pulling in as much material as I can... or just doing the old "3-weld" deal, where you do one weld in the corner, then a weld on each side of it, overlapping slightly in the middle of the first weld....
Mike